Rotary liquid seal



oct. 2s, 19,41; J. R BARR 2,260,820

ROTARY LIQUID SEAL Filed Aug. 30, 1939 Fig. Z.

Inventor: James R Barr;

by /Va/,w/ Mw! His Attorney Patented Oct. 28, 1941 'ROTARY LIQUID SEAL James R. Barr, Pittsfield,` Mass., assigner to General Electric Company, a corporation of New York Application August 30, 1939, Serial N0. 292,654

3 Claims.

My invention relates to rotary liquid seals. An electrical transformer is frequently provided with taps in one of its windings, the taps being connected to a` ratio switch so that the voltage ratio ing leakage and escape of the liquid along the shaft to the outside of the casing.Y The general object of the invention is' to provide an improved seal for preventing escape or owof liquid along a rotary shaft. While the invention will be described in connection with a liquid immersed transformer provided with a switch for varying or adjusting its voltage ratio, it will be obvious that the invention has many other applications wherever prevention of leakage of liquid along a rotary shaft is desirable.

The invention will be described in connection with the accompanying drawing, in which Fig.- 1 shows a liquid immersed transformer provided with a ratio switch operated by a sealedI shaft constructed in accordance with the invention, the view being shown partly in section; and Fig. 2 isv an enlarged view of the switch operating shaft provided with a seal arranged in accordance with the invention.

Like reference characters indicate similar parts in both figures of the drawing.

Y,The transformer I shown in Fig. 1 has one of 4its windings provided with taps connected by tap connections with a ratio switchA I2. The transformer I0, tap connections II, and ratio switch I2 are immersed in an insulating liquid I3 Within a casi'ng I4. 'I'he ratio switch I2 is' operated bya shaft I5, extending through an opening I6 in the side of the casing |4, the shaft being formed in two parts connected by beveled gears I5', so that' its outer part may be extended downwardly to a hand wheel I'I conveniently accessible beside the transformer. The side opening I6 extends through a tubular extension I8 of the casing I4. may be formed in sections for convenience of assembly, the' sections being secured together by gasketed or other sealed joints I 9. The outer s ection of the tubular extension I8, as shown in the drawing, forms a hollow casing 20 surrounding This tubular extension I8 (Cl. 30S-36.2)

the shaft I5 and enclosingrthe sealing means for preventing escape of the liquid I 3 along the shaft.

A seal disc 2| surrounds the shaft I5 and is secured and sealed to the shaft between a nut 22 and a flange 23, formed on the shaft. The disc 2| fits tightly against an internal-seal seat 24 formed on the inner surface of the casing 20, the disc 2| being forced into constant engagement with the seat 24 by a spiral spring 25 surrounding the shaft and compressed between the flange '23 and the inner race 28 of a ball bearing 26, the bearing fitting around the shaft and inside the casing near the outer end of this casing. 'I'he race 28 of the ball bearing 26 rotates with the shaft but is free to move along the shaft i I5 and the outer race 29 is freeto move along the inner surface of the casing 20 the latter race being held in adjustable position byl a ring 26' surrounding the shaft and threaded into the outer end of the casing 20. The compression of the spring 25 may be adjusted by the ring 26 so that pressure sufcient to prevent leakage of the liquid I3 may be maintained between the seal disc 2| land its seat 24 throughout' rotation of the shaft. The ring 26 may be held in adjusted position by a set screw 21. The seat 24 preferably faces toward the outer end of the casing 20 as shown in Fig. 2, so that the adjusting ring 26' may be easily accessible.

The seal disc 2| is secured to the shaft I5 so that it rotates with this shaft during any adjust-l ment fof the switch I2; the disc 2|, therefore,

' rubs against its seat 24, whenever the ratio switch I2 is adjusted and it should, therefore, be formed of some tough materal, such as a suitably moulded compound, which will resist wear and have a reasonably long life. The spring -25 being arranged between the ange 23 and the inner bearing race 28 will rotate with the shaft so that a smoothvconstant pressure is exerted thereby against the flange to maintain the seal disc 2| upon the cooperating seat 24 throughout movement of the shaft. A shaft constructed with a seal in accordance with the invention for operatinga transformer ratio switch has been operated under test conditions through a angle several ,hundred thousand times and under a pressure between the seal disc 2| and its seat 24, suflicient tok prevent Yany appreciable leakage of liquid throughout the test.

'Ihe invention has been explained by describing and illustrating a particular embodiment thereof,

but it .will be apparent that vchanges may be' made without departing from the spirit of the invention and the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States; is: A

1. A rotary shaft, a casing surrounding the shaft and having an internal seal seat, a seal disc secured to and sealed around the shaft and fitting said `seat, a bearing for the shaft, said bearing having a part rotatable with said shaft and slidable thereupon, a spring compressed between said disc and said bearing part for forcing said disc against said seat and a member threaded in said casing `operatively associated with said bearing for adjustably positioning said bearing including said part relative to said casing.

2. A rotary shaft, a casing surrounding the shaft and having an internal seal seat, a seal disc secured to and sealed around the shaft and cooperatively tting with said seat, a bearing for said shaft, said bearing having a first part rotatable with said shaft and slidable thereupon, a

spring compressed between said disc and said first bearing part for forcing said disc against said seat, said bearing including a second part slidably arranged in said casing, a member adiustably arranged in said casing for engaging with said second bearing part, said bearing including a third part whereby movement of said second part by said adjustably arranged member will eifect'a corresponding movement( of said first bearing part.

3. A rotary shaft, a casing `surrounding said shaft and having an internal seal seat, a ange on said shaft, a disc secured to and sealed around said shaft and against said flange, said disc co-A operatively tting with said seat, a bearing for said shaft, said bearing having a first part slidable on said shaft and rotatable therewith, said bearing having a second part slidably tted in said casing, said bearing having a third part arranged between said flrst and second parts substantially precluding relative axial movement therebetween, a spring compressed between said flange and said first bearing part for forcing said disc againstL- said seat, and adjusting means threaded into said casing engaging said second bearing part for varying the compression of the spring to adjust the pressure between said disc and said seat.

JAMES R. BARR. 

